1. Field of the Invention
The present invention relates to a learning type signal recording and reproducing apparatus for recording/reproducing a signal on/from a recording medium such as an optical disk, a magneto-optic disk, a magnetic disk, and a magnetic tape.
2. Description of the Related Art
As one of the prior art techniques for reproducing a signal recorded on an optical disk, a magnetic disk, a magnetic tape, and the like, an apparatus which converts a detected signal into "0" or "1" based on a predetermined threshold and outputs the result as a reproduction signal has been proposed.
The configuration of such a conventional signal recording and reproducing apparatus is schematically shown in FIG. 8. Referring to FIG. 8, a signal recorded on a recording medium 81 is detected by a signal detector 82. The signal detector 82 is connected to a comparator 83, to which a threshold memory 84 is also connected. The signal detected by the signal detector 82 is input into the comparator 83, and compared with a threshold read from the threshold memory 84 by the comparator 83. The comparator 83 outputs "1" when the signal from the signal detector 82 is greater than the threshold or "0" when it is smaller than the threshold as a reproduction signal. In this way, the conventional signal recording and reproducing apparatus can provide stable signal reproduction which is not influenced by signal distortion due to noise and the like.
However, the conventional signal recording and reproducing apparatus has a disadvantage as follows: When a signal having irregular waves as shown in FIG. 9 is input into the comparator 83 from the signal detector 82, for example, a wrong reproduction signal may be output in some cases. This wrong signal reproduction may be caused when the signal detected by the signal detector 82 includes noise or may be caused by various factors such as the difference between recording media used and the difference in the conditions under which the signal detection is performed.